Temperature of antenna wire
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| Sep 18th 2011, 02:28 | |
W7DSTJoined: Feb 12th 2004, 12:24Total Topics: 0 Total Posts: 0 |
I am hanging a G5RV antenna from a Pine tree in an inverted V configuration. The max RF output will be 200 watts SSB and CW. I am concerned about the temp of the wires starting the tree on fire. O.K. I love the tree so give me a break if my concern is invaled. Tnx, Bob |
| Sep 18th 2011, 05:33 | |
KE8DOJoined: Apr 4th 1998, 00:00Total Topics: 0 Total Posts: 0 |
I used to work for VOA and I seen plenty of antenna wires melted and falling to the ground, but we were running 250KW AM, that is 1,000 KW PEP, a little more power. A bird or other animal on the transmission line or antenna could cause arcing to start. 200W is not going to heat up the wire unless you have arcing due to a loose connection or the wire is touching a tree limb. You may want to use insulated wire and keep the wire well away from the tree limbs. |
| Sep 21st 2011, 14:22 | |
W1RFIAdminJoined: Jul 25th 2011, 14:25Total Topics: 0 Total Posts: 0 |
Unless you are using very thin wire, 200 watts should not cause enough current to melt wire. (The National Electrical Code specifies #12 copper-clad steel wire for outdoor antennas.) At anything over QRP levels, it's a good idea to make sure the antenna wire itself is not going to be in contact with the tree, especially at the ends of the wire where voltages can get very high. Under some circumstances, if the ends of the antenna were in contact with the tree, it could arc over to the tree, or its leaves. Even it doesn't start a fire, the sparking that can occur would be an RFI issue in the neighborhood. 73. Ed Hare, W1RFI ARRL Lab |
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